This invention relates to refrigeration apparatus for detachable joining to shipping containers and especially shipping containers refrigerated on shipboard using cold air which is introduced and removed from said containers by means of portholes provided therein.
Maurer U.S. Pat. No. 3,675,439 describes a detachable apparatus for the supplying portside refrigeration to perishable products which have reached their point of destination. The products are in the storage container to which refrigerated air has been supplied on board ship, but once unloaded at the point of destination refrigeration is supplied by spraying fluid such as liquid nitrogen or carbon dioxide from the detachable refrigeration apparatus. This apparatus includes a refrigerant storage tank, a flow control mechanism, a temperature sensing device which signals the control mechanism and associated pipings and fittings which are detachable and can be installed dock side on those shipping containers which have been equipped with a Maurer refrigerant dispensing means. The latter as described in the Maurer patent comprises a perforated conduit permanently installed in the upper portion of the shipping container and extending the full length of the container. The as described Maurer apparatus is not suited for shipping containers which are not equipped with the permanent spray refrigerant dispensing means and the cost of adding such means to existing containers represents a sizable investment.
The objects of this invention are to provide a cryogenic refrigeration apparatus for use with thermally insulated shipping containers which apparatus does not require substantial alterations and additions to existing shipping containers, attaches to the container, occupies extremely little space compared with its refrigeration capacity, is virtually maintenance free, is self-contained and capable of providing substantially uniform desired temperature within the shipping container.